Boudinage

 Boudinage, it's a geological word which is came from French boudin, “sausage”, it represents structures formed by extension , a cylinderical structures making up a layer of deformed rock. This structure forms when a rigid tabular body like hornfels stretched and deformed among less competent surroundings .

Boudinaged calcite vein. Notice how matrix flows around the boudins.

 Elba island, Italy. PPL image, 2x (Field of view = 7mm)

Seen in cross section, the cylinders, or boudins, are generally barrel-shaped but may be lenslike or rectangular. They commonly lie adjacent to each other and are joined by short necks to give the appearance of a string of sausages . The thickest boudins are about 20 m thick, and the thinnest about 1 cm , they come in different scale , they can be microscopic to lithospheric and can be founded in all terrans .

the interest of studying of the boudinage is in providing insights to the forces involved in tectonics deformatin of rocks and their strength.

The geometry of boudins is largely controlled by whether boudins are separated by extension or shear fractures, and the influence of plastic versus brittle deformation mechanisms. Asymmetric boudins may indicate non coaxial deformation. From Structural Geology, Fossen, H. (2010)

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